Relay switch assembly having improved switch contact actuating means especially suitable for use in the ignition control unit of a fluid burner



Apnl 11, 1967 A. D. WYLAND ETAL 3,314,028

RELAY SWITCH ASSEMBLY HAVING IMPROVED SWITCH CONTACT ACTUATING MEANS ESPECIALLY SUITABLE FOR USE IN THE IGNITION CONTROL UNIT OF A FLUID BURNER Filed Dec. 22, 1965 3 Sheets-Sheet 1 //21/e1? Za r's A/wh Q. VKg/aflmi Dawn l/V. Dcvwgy, by HAM Altar/7e39 3,314,028 NTACT April 1967 A. D. WYLAND ETAL RELAY SWITCH ASSEMBLY HAVING IMPROVED SWITCH CO ACTUATING MEANS ESPECIALLY SUITABLE FOR USE IN E IGNITION CONTROL UNIT OF A FLUID BURNER 3 Sheets-Sheet 2 Filed Dec. 22, 1965 All/l D. Mg/ana,

.Danrz W 0627225,

April 11, 1957 A. D. WYLAND ETAL 3,31

RELAY SWITCH ASSEMBLY HAVING IMPROVED SWITCH CONTACT ACTUATING MEANS ESPECIALLY SUITABLE FOR USE IN THE IGNITION CONTROL UNIT OF A FLUID BURNER Filed Dec. 22, 1965 5 Sheets-Sheet 5 mm L Fig.8

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(47 95 vol rs) United States Patent RELAY SWITCH ASSEMBLY HAVING IMPROVED SWITCH CONTACT ACTUATING MEANS ESPE- CIALLY SUITABLE FOR USE IN THE IGNITION CONTROL UNIT OF A FLUID BURNER Alvin D. Wyland and Dann W. Denny, Morrison, lll., as-

signors to General Electric Company, a corporation of New York Filed Dec. 22, 1965, Ser. No. 515,644 Claims. (Cl. 335-128) The present invention relates to an improved relay switch assembly especially suitable for use in the ignition control unit of a fluid burner, and more particularly, to such an assembly which is capable of operation under high temperature conditions in an ambient containing foreign substances, such as small particles of lint and the like.

In clothes dryers, space heaters and other types of gas fired equipment, it is common practice to use a master control system for operating the ignition electrodes of the gas burner and for regulating the supply of gas to the humor. The system disclosed in Patent 3,207,204 issued on Sept. 21, 1965, to P. W. Thompson is representative of those in use today. As will be seen from the disclosure of this patent, the Thompson system incorporates a relay switch assembly, which along with other devices, controls the supply of power to the starting circuit branch of the control system and to the control solenoid of the gas valve which in turn regulates thesupply of gaseous fuel to the burner. Components of the system, including the relay switch assembly, are usually mounted as a unit adjacent to but externally of the combustion chamber so that the combustion responsive means of the system carried by the unit, such as a flame detector tube used to signal the presence and absence of a flame at the burner, may be positioned in the desired proximity to the gas burner. That is to say, the flame detector tube projects into the combustion chamber next to the gas burner where the temperature may reach 135 0 F.

In order to provide a cooling effect on the switching and related components of the control unit, the unit is generally located in the air flow path to the combustion chamber. Since, however, the air flowing over the unit toward the chamber contains foreign substances, such as minute particles of lint and thelike, the relay switch assembly and other switching devices are normally housed within an enclosure or box to protect them from contamination by the foreign substances.

In spite of these efforts made to cool the ambient of the relay switch assembly and the precautions taken to protect it from contamination by foreign substances, as a practical matter, the assembly in many applications is still subjected to relativelyhigh ambient temperatures in the neighborhood of 235 F. In addition, due to their minute size, foreign particles still tend to penetrate into the confines of the enclosure from the ambient outside of the unit and interfere with the proper operation of the relay contacts. This interference results from the adherence of the particles to the contact urfaces, the buildup of particles being such that they may ultimately prevent a closed circuit through the contacts and premature failure in the circuit controlof the gas valve solenoid which, in turn, causes an inoperative valve and lack of gaseous fuel supply regulation to the burner. Consequently, it is extremely desirable, if not essential, that the relay switch assembly not only function in a satisfactory manner in a high temperature environment, but also be capable of satisfactory operation even in an ambient containing minute foreign substances, such as particles of lint and the like.

It is therefore a primary object of the present invention 3,314,928 Patented Apr. 11, 1967 vide an improved, yet economical, relay switch assembly which is capable of satisfactory operation under relatively high temperature conditions in an environment containing foreign substances and is further readily manufactured and assembled.

In carrying out the objects in one form, we provide an improved relay switch assembly, especially adapted for use in an ignition control unit of a fluid burner application, where it might be subjected to a high temperature environment containing small foreign particles. The assembly comprises an armature pivotally mounted for swinging one armature section alternately between open and closed positions with respect to electromagnetic means. A spring member is employed to bias the one armature section toward the open position.

The switch means of the assembly in the illustrated embodiment includes spaced apart first and second switch elements each having one end secured at one location and the other end carrying contacts facing one another. The second element is operable in response to the position of the one armature section and is resiliently movable between open and closed contact positions relative to the first switch element. The contact surface of the second element is sharply curved and elevated from the resilient member carrying it which has a dimensionally reduced cross-section such that it may be deflected near the contact of the second element. During operation of the switch means, the contact surface of the second element is urged across the contact surface of the first element between initially engaged and fully closed contact positions.

The switch actuating means which operatively connects the armature and second switch element together is a relatively stiff link, preferably formed of heat insensitive insulating material, having slightly flexible yet sturdy, spaced apart lateral extension mean respectively connected or coupled to another armature section and to the free end of the movable switch element. In addition, the spaced apart lateral extension means are integrally joined together at one end as a unit by an intermediate link section which is laterally off-set from the respective coupling or connections of the armature section and movable switch element with their associated lateral extension therebetween.

means. Among other things, this construction permits some relative movement between the coupled together assembly components as the one armature section moves between the open and closed positions.

With the foregoing arrangement, the relative movement of the contact surfaces for the switch elements produce an unusually effective scrubbing action as the second element is moved between the initially engaged and fully closed contact positions to prevent build-up of foreign material In addition, the assembly may be employed in applications having a high temperature environment, if such is desired. In spite of these advantageous and beneficial features, the assembly is economical to manufacture and the assembly components easy to install.

The subject matter which we regard as our invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. Our invention, itself, however, both as to its organization and method of operation, together with further objects and advantages thereof may best be understood by reference to the following description ta-ken in connection with the accompanyin g drawings.

In the drawings:

FIGURE 1 is a partial elevational View, partly broken away of a master control unit for use with a gas burner, the unit having the cover and certain other parts removed to show the preferred form of our invention incorporated therein, with contact elements and relay armature of the fuel valve controlling ignition relay assembly in their respective open positions and the relay coil deenergized;

FIGURE 2 is a plan view of the part of the unit shown in FIGURE 1;

FIGURE 3 is an enlarged, exploded view of the electromagnet armature, movable contact element, and linkage arrangement of the valve controlling ignition relay assembly;

FIGURE 4 is a partial elevational view showing a part of the valve controlling relay assembly seen in FIG- URE 1, with the relay coil energized and the relay switch contacts shown in the initial engaged position;

FIGURE 5 is a view taken along line 55 in FIG- URE 4 toshow part of the relay assembly;

FIGURE 6 is a view similar to FIGURE 4 except that the relay armature is in the closed position and the relay switch contacts are in the fully engaged or closed position;

FIGURE 7 is a modification of the linkage of FIG- URES 1-6 connecting the relay armature and movable switch contact element together; and

FIGURE 8 is a graph showing two representative curves depicting the armature displacement of the relay as compared with the available and load forces respectively on the armature.

Referring now in more detail to the drawings, and in particular to FIGURES 16 for purposes of disclosure, one form of the present invention has been illustrated in connection with a gas ignition control unit 10 of the type revealed in the Thompson patent mentioned above. As best seen in FIGURES 1 and 2, the individual components of the control are housed within the confines of a control box formed by a U-shaped frame 11 which serves to support the components in the desired location and a standard complementary cover plate (not shown) to complete the enclosure as shown by Thompson. A combustion responsive means in the form of a flame detector tube 12 is supported in an aperture provided in leg section 13 of the U-shaped frame and projects away from the frame so that the tube can be properly positioned with respect to the gas burner located within the combustion chamber (not shown). 7

Between frame upright legs 13, 14, the frame mounts a main relay switch assembly constructed in accordance with one form of our invention and denoted generally by numeralZl, which may be used to regulate the supply of power to a gas valve control coil (not shown). In the illustrated exemplification, assembly 21 includes a relay coil 22 surrounding a pair of spaced apart upstanding core legs 23, 24 of a magnetic core mounted on frame 11 adjacent upright leg 14 and a magnetic armature or operating arm 26 pivotally supported intermediate sections 27, 28 by a sturdy bracket 29 bent into the general form of a U. As best seen in FIGURES 1, 2, and 5, the pivot for armature 26 is formed by stamping out an enlarged slot 31 in bracket 29 at the appropriate location near one end of bracket overhang 32, which provides a stop for armature section 27 in its open position with respect to the termination of core leg 23. A suitable recess 33 is formed in the bottom wall of the slot 31 for accommodating a complementary intermediate section 34 of armature 26 and serves as the pivot for the armature. Once armature 26 and bracket 29 have been assembled together by inserting armature section 28 through the slot and arranging the armature into the desired location on the bracket, bracket projection 36 may be bent downwardly into the illustrated position over armature section 34 to lock the armature in place on the bracket thereby preventing its inadvertent disassembly. A coil spring 37 is employed as the means for biasing armature section 27 toward the open position (FIGURE 1), where it engages a magnetic isolating brass eyelet 30, and for maintaining armature section 34 firmly in the bracket recess 33. The spring is held under tension between armature tab 38 on the one end and at the other end by bracket tab 39, the spring being installed after the armature and bracket have been assembled together.

Turning now to the cooperating relay switching elements of assembly 21, denoted by numerals 41, 42 in the various figures, the pair of elements are supported in cantileverfashion at one end in a terminal stack 43 mounted on the U-shaped frame 11 near upright leg 13. A conventional strip of mica or the like 44 electrically separates the secured ends of elements 41, 42 in the stack, the elements being adapted for quick connection in the control circuit by any suitable means, such as lateral quick connect terminal members 45, 46 (FIG- URE 1) stamped out of electrically conductive strip material and arranged in the stack in engagement with the associated elements 41, 42. The other control components of the unit 10, also carried by frame 11, have been shown in phantom block outline in FIGURES 1 and 2 to permit illustration of the details of assembly 21. The control components may take any suitable form, such as those revealed in the Thompson patent, and are not critical to the present invention.

With specific reference to upper relay element 41 (as viewed in FIGURES 1 and 2) it includes a relative stiff rectangular shaped, blade member formed of suitable electrically conductive strip material carrying adjacent its free end a single head, fixed contact 47 having a generally flat contact surface facing downwardly. Contact 47 is preferably constructed of suitable material which tends to discourage cold weld sticking, such as silver with a cadmium oxide. The longitudinal axis of element 41 is approximately parallel to the bight portion of frame 11. the element being spaced therefrom to allow sufficient room for element 42 to move freely between open and fully closed contact positions (FIGURES 1 and 6 respectively) without interference from the frame. A rectangular shaped piece of heat insulation 49, e.g. polyester tape having adhesive material on one side, isattached to frame 11 beneath elements 41, 42 to furnish a heat shield for the relay switch.

With specific reference to element 42 which serves as the movable contact means of the relay switch assembly, it is preferably fabricated from relatively thin, electrically conductive and resilient strip material, such as beryllium copper. In its mounted position on frame 11, element 42 has itslongitudinal axis generally parallel to and spaced from the axis of element 41 and carries a single-headed movable contact 48, composed of suitable material (e.g., fine silver), with. its contact surface facing contact 47.

It will be seen from FIGURE 1 that in the unactuated or open switch position relative to the fixed switch contact element 41, movable element 42 is bent downwardly at an angle from its end in stack 43, approximately 10 in the exemplification, to provide a normally open switch having a suitable contact gap, All-.04, inch by Way of example. In the open contact position (FIGURE 1) and in the initial engaged contact position (FIGURE 4), the center line of the contact surface for contact 48 is slightly offset, toward the free end of element 42, from the center of fixed contact 47. From. a comparison of FIGURES 4 and 6, it will be appreciated that during movement tothe fully closed contact position the sharply curved contact surface of contact 48 turns away from the free end of element 42 as element 42 deflects and contact 48 moves across the contact surface of fixed contact 47 for an angle 0, preferably 2-8 degrees, to produce a highly effective scraping or scrubbing action between the cooperating contacts for a distance of 8-12 mils in one application. The contact surface area of contact 47 and height of the contact surface of contact 48 above the blade of element '42 should be dimensionally great enough to insure a sufiicient total length of travel and motion for contact 48 across the surface of contact 47 to achieve the desired cleansing action. By Way of example, if contact 47 has a diameter of 0.125 inch and a height of 0.032

inch, the height of contact 48 should be in the neighborhood of 0.100 inch.

In order to provide the desired sharp turning movement of contact 48, the resilient member or blade of element 42 is not only relatively thin with the grain extending in the direction of its longitudinal axis; e.g., 0.005 inch, but, in addition, it includes a reduced transverse dimension or cross-section at region 51 adjacent contact 48 on the side of the element opposite from switch actuating region 52 which contains a slot 53 for loosely receiving a switch actuating link to be described hereinafter. In the illustrated form, element 42 gradually increases in width from region 51, the smallest transverse dimension of the element, to its normal width at bend 54. This configuration allows the greatest amount of deflection for element 42 to take place in the vicinity of contact 48 in the manner shown in FIGURE 6 (slightly exaggerated) so that the desired angular motion of the contact surface for contact 48 may be attained.

It has been found in actual practice that the elements 41, 42, when constructed in the manner illustrated and described above, achieved an unusually effective scraping and cleaning action of the contact surfaces as contact 48 was turned through an angle in the range between 2-8 degrees. In addition to the dimensions given above, by way of exemplification, for the best results in actual practice, element 42 also included the following nominal measurements in inches (see FIGURE 3) for one particular size assembly 21: transverse width at. region 51:0.125; a (between center of slot 53 and center of contact 48)=0.187; b (between center of contact 48 and region 5 1)=0.25 inch; c=1.04; and 11:025.

In the illustrated exemplification, a switch actuating link 61 operatively connects region 52 of movable switch element 42 to armature section 28 for actuation in response to the position of the armature 26. In the form illustrated by FIGURES 1-6, link 61 is a sturdy singlepiece elongated member, generally rectangular in crosssection, having an upper lateral arm on U-shaped extension 62 with the legs thereof loosely accommodated in complementary and opposed slots 63, 64 (FIGURE 3) of the armature section 28. The lower part of the link, as viewed in the figures, is connected to the region 52 of element 42 by a lateral link arm or extension 66 which projects from the same side of the link as upper extension 62. Lateral extension 66 is disposed beneath element 42 and has a protuberance 67 projecting upwardly through element slot 53. A positive connection is completed at each extension by covering the connection with suitable adhesive material 68, such as silicone rubber, vulcanized at room temperature which remains unhardened' at the elevated temperature to which the relay assembly will be exposed. This arrangement permits slight relative movement of the coupled together components at each link connection as the relay components transfer between the positions shown in FIGURES l and 6 to furnish a smooth operation. Moreover, the lateral link extensions, in spite of their free-ended construction, are capable of being placed under either tension or compression to transmit the force of spring 37'to element 42 for reasons which will be developed more fully below. A link fabricated from relatively stifi, electrically insulating materials, such as Textolite, melamine glass cloth laminate, or the like, not only furnishes the desired qualities mentioned above, and acts to electrically isolate the armature and switch element 42 but in addition, provides a link which will not be excessively sensitive to elevated temperatures, especially desirable for gas burner applications. Another advantage of employing a link having the illustrated configuration is the unencumbered space it provides directly over the free ends of the relay switch elements for receiving parts of other components in stacked relation with elements 41, 42.

Turning now to the operation of the embodiment shown in FIGURES 1 through 6, it will be recalled that FIG- URE 1 depicts the relay assembly components in their open positions. It will be assumed that in the application of assembly 21 in unit 10 that main relay switch contact 48, is normally in an open position when the control is in the cold condition. Thus, when there is a demand for combustion, control 10 is energized in response to the demand for heat and the coil 22 is excited through suitable conductor leads 25 connected in the proper control circuit for the particular application. Upon excitation of the coil 22, the electromagnetic force of attraction on the armature at section 27 overcomes the total bias at the other end of the armature resulting from spring 37 and movable element 42 (the load) to pull armature section 27 rapidly down from the open position (FIGURE 1) into the closed one. During such operation, link 61 will be placed in tension as it over comes the spring force in a downwardly direction of element 42 and the actuated assembly components will pass through the positions depicted in FIGURES 4 and 5 where switch contacts 47, 48 make their first or initial engagement with one another in the manner revealed by these figures. Continued movement of the armature will pivot armature section 28 and attached parts upwardly in the direction of the arrow in FIGURE 4 to the respective armature and switch positions of FIGURE 6. It should be noted at this time that between the initial contact engagement (FIGURES 4, 5) and fully closed contact position (FIGURE 6) the force exerted on the respective lateral extensions 62 and 66 willbe in opposite directions (as indicated by the arrows in FIG- URE 5) and the link, through actuating region 52 of element 42, will urge the contacting surfaces of contacts 47, 48 together with a preselected force transmitted through contact 48.

By virtue of the construction previously explained in connection with link 61 and contact element 42, movable contact 48 will be urged firmly against the contact surface of fixed contact 47 as it is forced across that surface through the angle 0 with a predetermined force; e.g., 20-60 grams for the size assembly previously identified. During this movement, a highly desirable scrubbing action takes place between contacts 47, 48 thereby tending to maintain the surfaces free from contamination of foreign particles. Once in the closed position, the armature section 27 will be held against core leg 23, shaded by copper coil 23a, until coil 22 is subsequently deenergized.

When conditions warrant the deenergization of the relay coil 22, the combined forces from the coil spring 37 through link 61 and deflected element 42 coact to return the assembly components to their respective positions shown in FIGURE 1, the open armature and switch contact positions.

It will be remembered that the lateral extensions of link 61 can be placed in either tension or compression and that they are positively connected with armature section 28 and element region 52. Consequently, if for some unforeseen reason, contacts 47, 48 would resist separating after relay coil 22 has been deenergized, the link is capable of transferring the force available from coil spring 37 to deflected element 42 for insuring the separation of the contacts. Further, due to the configuration of link 61, including the lateral extensions, a moment will tend to be established relative to element 42, thereby augmenting the interaction of spring 37, link 61, and element 42. Thus, adhesive material 68 should have suflicient strength to hold the .link and associated parts together to permit the efiective transfer of force through link 61 to region 52 of element 42 even when the link is placed under compression.

FIGURE 7 shows a modification of the link, denoted by numeral 71, which differs structurally from link 61 in the type of lateral extensions provided and the positive connection they make with armature section 28 and element actuating region 52. In this embodiment, the upper lateral extension (as viewed in the figure) is bifurcated, indicated by numeral 72, 73. The bottom surface of armature section 28 rests on bifurcation 72 while the upper part of the armature section, between armature slots 63, 64, fits ina recess 74 of bifurcation 73-to lock the armature in place and provide a positive connection. The lower lateral extension 76 is in the form of a pair of offset portions 77, 78 such that when region 52 of element 42 is properly located on extension 76, part of the region rests on lateral portion 77 and another part is disposed beneath extension portion 78 to provide a positive connection here, too.

During installation of link 71, the bottom extension 76 is assembled first with element 42 by sliding portion 77 through enlarged slot 53 and then turning the extension to the illustrated position. Thereafter, armature section 28 and the bifurcated part of link 71 may be snapped together by inserting armature section 28 between bifurcations 72, 73 to force the bifurcations slightly apart until the upper part of section 28 enters recess 74. Like link 61, link 71 can be placed in either tension or compression and has the same advantages as given in connection with link 61.

FIGURE 8 reveals armature displacement-force curves 81, 82 which are representative of a number of relay assemblies constructed in accordance with the illustrated embodiment of FIGURES 16 inclusive and having the component dimensions and forces already set out by way of example. The fully open relay air gap between the arrows in FIGURE 1 was .020-.60 inch. The'fully open contact gap was in the range of .010-.040 inch. Curve 81 shows the typical load force at the upper connection between armature section 28 and lateral link extension 62. while curve 82 represents the available magnetic force at 95 volts at the same location.

When the contacts become initially engaged (FIG- URE 4, Zero contact gap) the armature air gap, indicated between the arrows was in the order of .045/ .012 inch. Upon reaching the fully closed position of FIGURE 6, there was between 20 to 60 grams of force on the contacts. With the load force (curve 81) on the upper connections being substantially less than the available force 82, that is, the force resulting from the energized coil and armature, the operation of assembly 21 between the positions depicted by FIGURES 1, 4, and 6 was extremely smooth and relatively quiet. Moreover, the scrubbing action effected between contacts 47, "48 prevented build-up of foreign material between the contacting surfaces and satisfactory performance of the assembly was achieved over a long period of time.

It will thus be seen from the foregoing that we have furnished an improved relay switch assembly especially suitable for use in a high temperature environment which contains small particles of lint or other minute foreign substances. The assembly components are economical to manufacture and assemble, yet are capable of satisfactory operation over an extended period of time under adverse conditions.

While in accordance with the patent statutes, we have described what at present are considered to be the preferred embodiments of our invention, it will be obvious to those skilled in the art that numerous changes and modifications may be made therein without departing from the invention. For example, contacts 47, 48 could be double-headed and element 42 could mount a second contact surf-ace spaced from contact 48. It is therefore aimed in the appended claims to cover all such equivalent variations as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is: v

1; A relay switch assembly for use in an ignition control unit comprising a magnetic core; an armature pivotarmature section toward the open position; electromag netic means adapted to be energized for actuating said one armature section from the open to the closed position; switch means including spaced apart first and second switch elements having contact surfaces facing one another; said second switch element having a resilient blade movably supporting the associated contact surface between open, initially engaged, and fully closed contact positions relative to the first switch element; switch actuating link means connecting a second section of said armature to said second switch element for controlling operation of said switch elements in response to the movement of said armature; the contact surface of said second switch element being spaced outwardly from the blade and the area of the contact surface for said first switch element being dimensionally suflicient for effecting a scraping action of the contact surfaces between the initially engaged and closed contact positions; said resi lien-t blade having a reduced cross section and deflectable region adajcent the contact surface of said second switch element and being so formed as to produce approxim-ately the greatest amount of angular deflection of said second switch element in the vicinity of said defleota ble region adjacent the contact surface for sharply turning the contact surface of said second element as it travels between said initially engaged and fully closed contact positions whereby a cleansing action is attained between the contact surfaces.

2. The relay switch of claim 1 in which the resilient blade is supported near one end and gradually increases in width between said reduced cross-sect-ion and said one end.

3. The relay switch of claim 1 in which the contact surface of said first switch element is relatively flat and the contact sunface Olf said second switch element is sharply curved.

4. A relay switch assembly for use in an ignition control unit comprising a magnetic core; an armature mounted for swinging one armature section alternately between open and closed positions with respect to said magnetic core; spring means biasing said one armature section toward the open position; electromagnetic means adapted to be energized for actuating said one armature section from the open to the closed position; switch means including spaced apart firs-t and second switch elements having contact surfaces facing one another; said second switch element having a resilient member movably carrying the associated contact surface between open and fully closed contact positions relative to the first switch element; switch actuating. link means connecting a second section of said armature to said second switch element for controlling operation of said switch elements in response to the movement of said armature; said switch actuating link means including a lateral extension connected tO 6lCl'1 of said armature and said second switch element and an intermediate link section joining the lateral extensions together as a unit, said intermediate link section being off-set from both the connection of said second section of the armature and the second switch element with the associated lateral extensions whereby a turning moment may be established in said switch actuating link means relative to said second switch element.

5. The relay switch assembly of claim 4 in which the link means is formed of insulating material and the con-,

motion of said armature and of the second switch element with an associated lateral extension includes a slot formed in one of the connected members accommodating a portion of the other connected member.

6. The relay switch assembly of claim 4 in which the second switch element is secured at one endand has an actuating region at the other end, the connection of said armature and of the actuating region of second switch element with an associated lateral extension is positive, the lateral extension in one of the connections is generally U-shaped having separated legs with the associated section held between the legs thereof, and said link means is capable of being placed in either tension or compression.

7. The relay switch assembly of claim 4 in which the resilient member includes a dimensionally reduced and deflect-able region near the contact surface of said second switch element for turning that surface through a predetermined angle as the surfaces travel toward the fully closed contact position.

8. Switch means for use in a relay switch assembly comprising spaced apart first and second switch elements having contact surfaces facing one another; said second switch element including a resilient member fixedly supported at one end and movably supporting the associated contact surface near the other end between open, initial- 1y engaged, and fully closed contact posit-ions relative to said first switch element; the contact surface of said second switch element being spaced outwardly from the resilient member and the area of the contact surface for said firs-t switch element being dimensionally sufficient for effecting a wiping action of the contact surfaces between the initially engaged and fully closed contact positions; said resilient member including a dimensionally reduced cross sect-ion and defiect'able region adjacent the associated contact surface to produce the greatest amount of angular deflection for said resilient member in the vicinity of said deflectable region adjacent the associated contact surface for turning the contact surface of said second switch element sharply through a selected angle as it travels between said initially engaged and fully closed contact positions whereby said contact surfaces are maintained free of foreign substances by the wiping action.

9. The switch means of claim 8 in which actuating link mean-sis connected to said second switch element for operation thereof, said actuating link means being formed of heat resistant, insulating material and having a lateral References Cited by the Examiner UNITED STATES PATENTS 2,497,306 2/1950 Dandmeier 200166 2,818,48 1 12/1957 Nicolaus 200-166 2,91 4,632 11/1959 Neumann 20087 3,242,285 3/ 1966 Obszarny 200'--104 BERNARD A. GILHEANY, Primary Examiner.

J. BAKER, Assistant Examiner. 

1. A RELAY SWITCH ASSEMBLY FOR USE IN AN IGNITION CONTROL UNIT COMPRISING A MAGNETIC CORE; AN ARMATURE PIVOTALLY MOUNTED FOR SWINGING ONE ARMATURE SECTION ALTERNATELY BETWEEN OPEN AND CLOSED POSITIONS WITH RESPECT TO SAID MAGNETIC CORE; SPRING MEANS BIASING SAID ONE ARMATURE SECTION TOWARD THE OPEN POSITION; ELECTROMAGNETIC MEANS ADAPTED TO BE ENERGIZED FOR ACTUATING SAID ONE ARMATURE SECTION FROM THE OPEN TO THE CLOSED POSITION; SWITCH MEANS INCLUDING SPACED APART FIRST AND SECOND SWITCH ELEMENTS HAVING CONTACT SURFACES FACING ONE ANOTHER; SAID SECOND SWITCH ELEMENT HAVING A RESILIENT BLADE MOVABLY SUPPORTING THE ASSOCIATED CONTACT SURFACE BETWEEN OPEN, INITIALLY ENGAGED, AND FULLY CLOSE CONTACT POSITIONS RELATIVE TO THE FIRST SWITCH ELEMENT; SWITCH ACTUATING LINK MEANS CONNECTING A SECOND SECTION OF SAID ARMATURE TO SAID SECOND SWITCH ELEMENT FOR CONTROLLING OPERATION OF SAID SWITCH ELEMENTS IN RESPONSE TO THE MOVEMENT OF SAID ARMATURE; THE CONTACT SURFACE OF SAID SECOND SWITCH ELEMENT BEING SPACED OUTWARDLY FROM THE BLADE AND THE AREA OF THE CONTACT SURFACE FOR SAID FIRST SWITCH ELEMENT BEING DIMENSIONALLY SUFFICIENT FOR EFFECTING A SCRAPING ACTION OF THE CONTACT SURFACES BETWEEN THE INITIALLY ENGAGED AND CLOSED CONTACT POSITIONS; SAID RESILIENT BLADE HAVING A REDUCED CROSS SECTION AND DEFLECTABLE REGION ADJACENT THE CONTACT SURFACE OF SAID SECOND SWITCH ELEMENT AND BEING SO FORMED AS TO PRODUCE APPROXIMATELY THE GREATEST AMOUNT OF ANGULAR DEFLECTION OF SAID SECOND SWITCH ELEMENT IN THE VICINITY OF SAID DEFLECTABLE REGION ADJACENT THE CONTACT SURFACE FOR SHARPLY TURNING THE CONTACT SURFACE OF SAID SECOND ELEMENT AS IT TRAVELS BETWEEN SAID INITIALLY ENGAGED AND FULLY CLOSED CONTACT POSITIONS WHEREBY A CLEANSING ACTION IS ATTAINED BETWEEN THE CONTACT SURFACES. 